Subject: Re: [bitcoin-dev] Dealing with OP_IF and OP_NOTIF malleability

From: Oleg Andreev <[email-masked]>
Date: Fri, 6 Nov 2015 10:32:02 +0100

> One and zero should be defined as arrays of length one. Otherwise, it is still possible to mutate the transaction by changing the length of the array. 
> 
> They should also be minimally encoded but that is covered by previous rules.

These two lines contradict each other. Minimally-encoded "zero" is an array of length zero, not one. I'd suggest defining this explicitly here as "IF/NOTIF argument must be either zero-length array or a single byte 0x01".